I thought he had possession crossing the line. At least. Look at that punishing play on thursday. As more nfl stars diagnosed with permanent brain disease. Has sparked so many more questions about football. At a time where the nfl is more popular and profitable than ever now. A panel of experts to take on that debate. Here's dr. Richard besser with a closer look at the science, safety and possible solutions. Steelers backing off, playing zone. What a hit! Reporter: Football fans live for brutal blows. Look at james harrison. And a very serious hit james harrison lays out. Reporter: Morgan cox. And that one was a knockout. Literally. And let's hope that chris was okay. Reporter: What thrills the fans may be what dooms the sport. Are we looking at the end of football? Memory loss, depression and dementia. Former players like jimmy McMAHON, ARE SAYING What's good for football in its current form is lethal for the brain. Damaged pros compare cte to degenerative brain disease. On espn radio, quarterback brett favre said that he's losing his family. It's shocking to me that I couldn't remember my daughter playing youth soccer. Reporter: A former new york giant said that he complicated suicide. I was so depressed. Accelerating and driving through the guardrail and just going over. Reporter: It turns out the future of football may rest on this woman, she's a walking contradiction. She's a die-hard packers fan. In love with a sport that can physically devastate players. You get spots, spots, that's really typical of this disease. Reporter: Alzheimer's doesn't look like this? No. I see tragic stories under the microscopes, I have seen kids who have died in their teens with early stages of this die seize. Reporter: The question that i face as a pediatrician and when my kids wanted to play football, is the danger of concussions so high that doctors and parents should forbid it, can this sport be saved? I don't know. I just don't know. Reporter: I went to a practice in the heart of football country, athens, georgia, one of the many places that football players barely come up to my knees. Oddily enough, we're coming in kind of late. So, midgets start at 4. Reporter:4-year-olds playing football. A few weeks the nation's largest youth football association announced that participation has dropped 10% between 2010 to 2012. I want to hear a strong argument in support of the game, mark richt. A father of four. You have to wonder, is it a safe sport for our kids? I think our kids are soft. I don't think they're very tough. I think that's a little bit scary. Because there are some things that come up in life that are tough and you have to be able to handle it. Reporter: But his own team, is doing concussion research, right on the field. You'll see it on the screen. Yeah. Give it a hit. Using cutting-edge devices that might identify the forces that cause concussions so they can prevent them, that might help. Coach richt supports the research. I think all of these things being designed to help us understand more about concussions and those types of injuries, I think the better off we'll be. Reporter: The keys are education and independence. If he thinks a player needs to sit out the player is out, regardless of what the coach thinks. We sit down with every athlete in every sport and talk about the symptoms of concussion. If they have them, they can recognize them and seek help. Reporter: Have you seen any change over time in players reporting a concussion or the signs of a concussion on their own? A great example last year, in the fall, georgia football, we had nine concussions. Five of themf-reported. Reporter: Then I talked to some of the players. If you had a concussion, would you pull yourself out of the game? If I had a concussion, probably not. First day of football, guarantee three concussions. You're going to get how many ever degrees. I'm saying absolutely. Reporter: You'll take it. That's not a bad deal at all. And dr. Besser joins us now along with joe delambielleure. Mark fainaru-wada. And christine brennan. Welcome to you all. Joe, let me begin with you, you're wearing that hall of fame jacket. I saw your hall of fame speech, it was clear when you were giving that speech, football was always wanted to do. But, now, you have been diagnosed with cte. You say that you're part of forgotten generation of football players, do you feel betrayed by the nfl? I feel betrayed by the nfl and the union because we have no health insurance, that's a problem. For the guys who played before '93, we have subpoverty pensions and no health insurance. That's a problem. And even though there has been this multimillion-dollar settlement, $765 billion, designed to help players who have been injured. They have at will of programs, but they're hard to access and players, let's face it, we're all over 60. How many guys go on the internet? We're scattered all over the country with a union that's never helped us, the pre-'93 guys. Once you're done, you're done with the union. You do make the point. These pre-'93 guys, you're talking about completely different world in terms of pay. I was the number one pick. My salary was 24,000, 30,000. Nothing guaranteed. 30,000 a year? Yes. We played on natural turf was torn up. I have hearing loss in my left ear. There's no more blocks, no more wage. There used to be the suicide squat on special teams. They just changed that to special teams. And mark, you have done a lot of work, of course, looking at the league and how the league dealt with all of this, even this settlement, not going to go far enough for so many of the players? Well, I think there are real questions. We're talking about $760 million. There are real questions whether there's even enough money there. You have a lot of players suffering, while we have done reporting on this. Players wondering if in the end, is the money going to step up? Players who are going to opt out of the settlement. Lot of these guys feel very betrayed by the league's denial for two decades. I think now, as they try to get information about this settlement, it's really hard to come by, you have lawyers and players who are really frustrated not getting any answers. We're now in week 12 and there are virtually no details about this settlement at this point. Christine, how much the league really knew and should have known for so long? George, when they agreed to that settlement, the nfl didn't disclose what it knew and when it knew it. That would be valuable information. Mark did this great reporting on this, you have this situation where it's over, right? 750 million paid out. But, then, the news comes out about joe and about tony dorsett, and brett favre, and I think what we're seeing here, is the fact that this story is not going away and it will continue to be a part of our conversation as it should be, I think. And there's only about $10 million in this for research. It's pretty hard to deny the basic facts, though. Yeah, the concern I have in that settlement there's no admission that there is a problem with football. And if there's no admission of that, and you're only putting $10 million into research, how are you going to know that this sport could be made safe enough? That we still want to watch it and it will not do this. And what about below the nfl level, as we're seeing in the piece, these kids playing in college ball aren't going to own up that they had a concussion. They're going to go out and have it. If that's happening time and time again, are they going to be experiencing the same thing that pro players are? Joe, your son played college football at duke, are there any changes in the game that could sort of solve the riddle that makes it safer? I think there's tremendous changes in the game. No head slaps. There are lot of rule changes for the better of the game. So, I think they're doing the right thing, but for them to continue to do the right thing, they have to make it better for the guys who created this monstrosity of a league and they just don't do it. They're always negative. Think the nfl is ready to go farther? Well, I think there are two issues. There's the league itself and what nfl football is going to look like. We don't want it to changed. It's a brutal violent sport. We're all talking about that auburn finish. This is the sport. But you did have for two decades, what did the nfl know and when. I think we trace that in the book, quite frankly. They have known for two decades this issue is there, and while the commissioner and the league are making moves forward on this issue to mitigate it, at the same time, when the commissioner is asked now, is there a length between football and brain damage, we're going to let the doctors decide this. Wants to do right? Roger goodell has daughters who play lacrosse, and let's face the facts here, yes we're talking about football, let's move my boy or girl out of that sport, soccer, girl's soccer, the risk is huge. Whether it's soccer, ice hockey, baseball, softball, girls are much more likely to have concussions than boys. And that risk is there. You leave football. We're done with football. The risk exists in so many other sports. But, I do think there is a question, what will football look like 20, 30 years from now? And we don't know. Thank you all very much.

This transcript has been automatically generated and may not be 100% accurate.